1. Field of the Invention
This invention relates to a banded endless power transmission belt made primarily of polymeric material and to a method of making such a belt.
2. Prior Art Statement
Banded endless power transmission belts comprised of a plurality of belt elements and a tie band holding the elements together are well known in the art. Such banded belts are commonly used where it is impractical to use a single belt because such single belt cannot be made large enough, from a practical viewpoint, to transmit large rotational forces. Also, banded belts are used in applications where it is not desirable to use a plurality of independent belts because such independent belts may tend to slip or become wedged in their pulley grooves so as to prevent the cooperating action which is required to transmit large rotational forces.
Many types of banded belts have been proposed previously, and particularly in applications where each banded belt has belt elements covered with a suitable cover it is common practice to form and cover a number of belt elements independently and then independently form a tie band for the belt elements whereupon the independently formed belt elements and independently formed tie band are placed in a suitable curing apparatus to achieve simultaneous curing and bonding of the tie band to the belt elements. Following the curing action, the resulting construction is usually slit and trimmed to define banded belts each having the desired number of belt elements. However, the previously proposed belts, made essentially as described herein, are comparatively expensive due to the added maufacturing steps which are required and the tie bands thereof have a tendency to be more easily pulled away from their belt elements.
It is also known in the art to utilize special fabric material in the tie band of a banded belt to provide such tie band with extensibility to take into account various operating conditions.
Examples of banded endless power transmission belts are presented in the following:
A. U.S. Pat. No. 3,523,461 PA1 B. U.S. Pat. No. 3,564,933 PA1 C. U.S. Pat. No. 3,853,017 PA1 D. U.S. Pat. No. 2,182,461
It appears from A that a banded belt is provided in which the tie band is fastened in position by molding such tie band in position against the upper portion of the V-belt elements during the process of making the belt.
It appears from B that a bended belt is provided which comprises fabric covered belt elements and a tie band which uses a stress-relieved fabric which has warps and wefts disposed at an angle to each other which may range between 95.degree. and 155.degree..
It appears from C that a banded belt is provided which comprises fabric covered belt elements and a tie band which uses a knitted fabric material.
It appears from D that a belt construction is provided which appears to be made as a non-continuous strip which is then fastened by fasteners to define an endless configuration. Rubberized fabric layers are disclosed and it is stated that layers of fabric in the web preferably comprise lateral projections or continuations of the layers in the V portions, and may overlap if desired.